In the conventional safety helmet, vent openings are provided at the bottom-positioned marginal region of the viewing opening and are of a slot shape. With the visor being closed, an air gap is formed between the bottom-located marginal zone of the visor and the outer surfaces of the rim of the viewing opening facing this marginal zone. While driving a motorcycle, due to the resulting pressure head, air flows through this gap to the vent openings and, via the latter, into the interior of the helmet. Although the vent openings are located at the level of the driver's mouth, the incoming air stream is also conducted to the driver's eyes, which can lead to tearing of the eyes and eye irritation. Because the vent openings are arranged merely along the marginal zone of the viewing opening, the air stream passing therethrough into the interior of the helmet cannot adequately prevent fogging of the inside of the visor with precipitated moisture.
The integral safety helmet disclosed in German Utility Model No. 7,837,986 has a flat air-conducting part at the chin protector. This part extends obliquely into the interior space of the helmet. The free end of this part lies in the vision field of the visor. Because the air-conducting part has an outer contour corresponding approximately to the mouth and nose portion of the wearer of the helmet, this air-conducting part can avoid, if anything at all, merely a fogging of the inside of the visor by the air directly escaping from the mouth and nose of the helmet wearer, which air is oriented toward the visor. However, because such air can spread within the entire interior of the helmet, the air-conducting part--especially in case of low outside temperatures--cannot entirely preclude fogging of the inside of the visor.
Finally, it is known from U.S. Pat. No. 3,727,235 to provide a jet helmet--that is, a protective helmet of a different type than the safety helmet discussed hereinabove--with a protective shield. An air-conducting element is mounted to the obliquely downwardly extending marginal portion of this protective shield, facing the protective helmet, and extends along this marginal portion. The air stream produced during driving of the motorcycle due to a pressure head is conducted along this air-conducting element to the inside of the protective shield, whereby the latter is to be kept free of moisture precipitation and the fogging caused thereby. However, because the protective shield, as mentioned above, is arranged at a jet helmet completely open at its underside, the air entering via the air-conducting element is made turbulent by the air flow always ambient on the underside of the helmet and thereby can also be disadvantageously conducted to the driver's eyes. Another, quite considerable disadvantage resides in the conventional safety helmet. During driving in moist, rainy weather, air having a high moisture content or also water droplets can pass from the outside to the inside of the safety helmet so that the latter cannot be kept free of fogging under the aforementioned weather conditions.
It is, therefore, an object of the invention to provide a device in a safety helmet of the type discussed above, by means of which the inside of the visor is kept free of fog from moisture precipitation by a controlled air conductance effectively directed toward the inside of the visor but deflected away from the driver's eyes, wherein the air stream generated is to contain air free of droplets even during moist weather conditions. In this connection, such air conductance is to be effected also in case of varying velocities of the vehicle, if possible.